1. Field of the Invention
This invention relates generally to storage battery charging systems and, more particularly, to a method and apparatus for the charging of a battery wherein provision of the correct charging voltage is based on information received from the battery during the charging process for any given cycle and battery.
2. Description of the Related Art
A rechargeable battery requires periodic recharging during its useful life. Various methods are known for rapid charging of storage batteries, including means for terminating the charging process, but overcharging of the battery is a frequent result. Overcharging irreversibly consumes the negative electrode of lead acid batteries, thereby reducing its volume and resulting storage capacity. There are many different types, sizes and capacities of batteries. Each type, size and/or capacity of rechargeable batteries may require a different charging algorithm. The battery manufacturer may determine the appropriate charging algorithm, which can be implemented with a battery charger. A typical battery charger may comprise a microcontroller, a power interrupt controller, a power converter circuit, and a feedback circuit for the battery voltage and/or current (depending on battery type and design requirements).
By way of example, U.S. Pat. No. 3,597,673, Burkett et al —08/1971 is directed to a means of reducing time required to recharge a battery by applying a depolarizing/discharging pulse between charging pulses; U.S. Pat. No. 4,829,225, to Podrazhansky et al, 05/1989, discloses that a further reduction in charging time can be achieved by waiting for a specified period after the end of the discharge pulse before applying the next charging pulse; U.S. Pat. No. 5,307,000 to Podrazhansky et al, 04/1994, discloses method and apparatus for rapidly charging a battery by applying at least one charging pulse to the battery, applying a plurality of depolarizing pulses to the battery, the pulses being separated by wait periods, and repeating the charge and discharge procedure until the battery is completely charged.
U.S. Pat. No. 5,694,023, to Podrazhansky et al, 12/1997, relates to method and apparatus for rapid charging of a battery wherein, in sequence, a first charging pulse is followed by a depolarizing pulse; a first rest period during which a voltage is measured at a predetermined point therein; a second depolarizing pulse is applied; a second rest period during which a voltage is measured at the predetermined point therein; the difference between the voltages is measured; and the average charging current is decreased if the difference is greater than a predetermined amount. The average charging and depolarizing currents may be decreased by selectively changing pulse duration pulse amplitude or the pulse repetition rate, or any combination thereof; U.S. Pat. No. 5,729,115 to Wakefield, 03/1998 relates to apparatus for charging batteries of different types having a sensor connected to a circuit for identifying the particular type of received battery by voltage indicative of a particular battery type and supplying a charging current to the received battery in accordance with a specified charging algorithm applicable to the particular battery type.
US Patent Application Publication No. U.S. 2003/0015993 A1, published Jan. 23, 2003 relates to a battery charging system providing controlled charging in accordance with an algorithm utilizing historical battery data acquired while the battery is in service and during previous charge cycles. The historical battery data is stored in the memory of a battery management module and is used to provide parameters to a charging algorithm.
In view of the foregoing, there is a need for a real-time means for accurately determining the type of battery and the state of its charge during a rapid charging process, so that the process may be optimized to bring the battery to a fully charged position and the charging process promptly terminated thereafter.